Kim Kardashian leaves fans speechless with ‘unrecognisable’ snap of brother Rob

Kim Kardashian has treated her adoring admirers to a rare throwback photograph of herself and younger brother Rob – and they simply cannot cope.

Taking to Instagram on Thursday, the Keeping Up With The Kardashians star, 39, posted a sweet sibling snap of herself and Rob, 33, ‘looking cool’.

The genetically blessed pair appeared to be having the time of their lives as they posed up a storm for the camera in true Kardashian style.

Kim captioned the throwback snap: “We were cool”.

Naturally, the makeup mogul’s latest offering sent her fans into complete meltdown after they initially believed it to be a current photo of Rob, who has struggled with weight issues in recent years.

Kim Kardashian has treated her adoring admirers to a rare throwback photograph of her and her younger brother Rob – and they simply cannot cope (Instagram)

Eagle-eyed admirers couldn’t contain their excitement at the former reality star’s ‘fresh’ appearance.

“Oh my god. I thought this was a current photograph. Rob was so fresh and so hot,” gushed one fan.

“Wow! You are both so gorgeous. You were then and you still are!” another echoed.

The star is posting more photos than ever (Rob Kardashian/Twitter)

“Rob is unrecogniable here. What a handsome young man,” a third commented.

While a fourth quipped: “Is it bad that I find skinny Rob less attractive than big Rob? Either way, he’s so hot!”.

Kim’s throwback snap comes as Rob has reportedly committed to a healthy new routine in recent months - and his friends and family couldn't be happier.

Rob is looking better than ever after adapting to a lifestyle change (Instagram)

The proud dad-of-one has notoriously stayed away from the public eye in recent years, but he’s made some dramatic changes to his lifestyle and the results have given him a slimmed down frame and lots more confidence.

According to People, Rob is doing really well and his close pals are thrilled.

"Everyone is just thrilled about how well Rob is doing," a source told the publication.

"He is really doing excellent."

Rob made an appearance to celebrate his sister Khloe's 36th birthday and he was flooded with compliments over his trim physique (Instagram)

The insider went on to say that Rob "had a lot of work to do when it comes to his health and he continues to be very committed."

"He is happier and healthier," thanks to his health kick.

During the summer, Rob made an appearance to celebrate his sister Khloe's 36th birthday and he was flooded with compliments over his trim physique.

It appears that Rob has stepped out of his shell and has a newfound confidence alongside his new slimmed-down frame.